1. Field of the Invention
The present invention relates generally to a three-dimensional object model creation apparatus and method for creating three-dimensional object models by means of computer graphics (CG), as well as to a computer readable record medium having a three-dimensional object model creation program recorded thereon. The invention relates more particularly to a three-dimensional object model creation apparatus and method for creating the three-dimensional object models through the assembly of part models, as well as to a computer readable record medium on which is recorded a three-dimensional object model creation program.
2. Description of the Related Art
With the increasing use of multimedia computer systems in recent years, three-dimensional computer graphics using e.g., polygons are prevailing, so that a demand is also increasing for systems ensuring easy creation of three-dimensional models having high quality without any need for profound knowledge and experience of the computer graphics. Known as such a conventional method ensuring easy creation of the three-dimensional object models is for instance Method of Arranging Three-dimensional Object Models disclosed in Japanese Patent Laid-open Pub. No. Hei 7-175944. In this three-dimensional object model arrangement method, a three-dimensional object model to be created is first displayed in two-dimensional views consisting of side elevation, front elevation, top plan view, etc. Then, the operator designates reference points common to the two-dimensional views and designates positions of the thus designated reference points in a three-dimensional space through the input of coordinate values or the positioning of a cursor on the screen. This allows sequential displays of the two-dimensional side elevation, front elevation and top plan view in conformity with the reference points designated by the three-dimensional space, after which transverse, depth direction and upward sweeps are respectively effected to model them into three solid figures, which in turn are subjected to AND processing to create a three-dimensional object model. In cases where another part model is assembled to the thus created three-dimensional object model, the part model is displayed in two-dimensional views consisting of side elevation, front elevation, top plan view, etc., and then the operator designates on the two-dimensional views reference points common to the views. The operator further detects by visual observation the positions of the designated reference points to be assembled to the model in the three-dimensional space and designates them. This will allow sequential displays of the side elevation, front elevation and top plan view of the assembling part in conformity with the reference points designated by the three-dimensional space, after which transverse, depth direction and upper sweeps are respectively effected to model them into three solid figures, which in turn are subjected to AND processing to create a three-dimensional part model for assembling.
In such conventional three-dimensional object model creation processing, however, the three-dimensional object model is assembled through the repetition of the simultaneous operations of the creation and assembling of the three-dimensional part models, in which creating operation the sweeps are effected with the two-dimensional views displayed in the three-dimensional coordinate space to create solid figures to be subjected to the AND processing, with the result that an increased number of parts are required with the extremely elongated time for the creation of a three-dimensional object model. In addition, assembling positions of the part model are designated by the operator as reference point three-dimensional coordinate values through the visual observation of the assembling positions on the three-dimensional object model in the process of assembly, so that the positional offset error is relatively large making it difficult to provide the accurate assembly of the three-dimensional object model. For this reason, the operator must perform additional adjustment for the positional offset of the assembling parts after the assembling, resulting in further increased labor hours.